2-[Tris(trimethylsilyl)silyl]ethyl (meth)acrylate is a useful monomer to form a polymer for use in bi-layer photoresist to be processed by lithography using excimer laser light. In the prior art, 2-[tris(trimethylsilyl)silyl]ethyl methacrylate is prepared by an esterification process of reacting a corresponding alcohol, that is, 2-tris(trimethylsilyl)silylethanol with methacryloyl chloride (see Sooriyakumaran et al., SPIE, Vol. 3333, p. 219 and Allen et al., U.S. Pat. No. 5,985,524). The process starting from the acid chloride and the alcohol in these references, however, has the following problems when it is carried out on an industrial scale. The reaction is usually effected using more than an equivalent of a base in a solvent. The acid chloride should be handled with caution since it is corrosived moisture sensitive. Work-up process, including extraction and concentration step, is necessarily required.
On the other hand, 2-[tris(trimethylsilyl)silyl]ethanol is synthesized by reaction of a silicon metal reagent, tris(trimethylsilyl)silyllithium with low-boiling ethylene oxide (boiling point 10.7.degree. C.) (see Brook et al., Organometallics, 1984, 3, p. 1317). This synthesis process also encounters difficulty upon industrial implementation because the awkward-to-handle compound is used.
Also known in the art is the synthesis of 2-[tris(trimethylsilyl)silyl]ethyl acetate by reaction of tris(trimethylsilyl)silane with vinyl acetate (see Kopping et al., J. Org. Chem., 1992, 57, p. 3994). It is also contemplated to synthesize 2-[tris(trimethylsilyl)silyl]ethanol by hydrolyzing or reducing the 2-[tris(trimethylsilyl)silyl]ethyl acetate. Another known example is reduction with lithium aluminum hydride (see Allen et al., U.S. Pat. No. 5,985,524). This process, however, encounters more difficulty because two steps of alcohol formation and esterification reaction are involved.
Another problem is that the intermediate 2-[tris(trimethylsilyl)silyl]ethanol is impossible to purify by distillation since it is a crystal having a melting point of about 150.degree. C. Purification by recrystallization is industrially troublesome, and a substantial loss is inevitable.